Not Applicable.
The present invention relates to a backpack. More specifically, the present invention relates to a backpack having a modular pack frame formed from a flexible contoured material that distributes the load of the backpack comfortably to the user""s body. The pack frame does not become distorted when loaded due to the reinforcements in the backpack and the manner in which the pack frame and pack bag are attached to one another.
Backpacks, and particularly backpacks capable of holding contents having a large volume or weight, typically include rigid, tubular frames that support the weight of the pack bag. These frames are secured to the user""s body at a pair of shoulder straps and a hip belt that act together to maintain the frame at a small distance from the back of the user. The downward load of the backpack is only felt at the user""s shoulders and at the hip belt since the frame does not contact the user""s back. While frames of this type provide a great deal of support for the contents of the bag, they are often uncomfortable and unwieldy. Also, the backpack""s contents tend to cause the pack bag to sag with the load being focused near the small of the user""s back on the hip belt and not at the desired position at the outer lumbar region of the user""s back near the outside of the user""s hips. A number of attempts have been made to properly transfer the load created by a rigid frame backpack. One particularly device is the flexible harness system disclosed in U.S. Pat. No. 5,762,251 to Gleason.
Another solution to the problem of ineffective load distribution has been to incorporate xe2x80x9csoftxe2x80x9d frame sheets within the pack bag. These frames are made from flexible material contoured to the shape of the user""s body. Typically, the frame sheets are manufactured from an aluminum or molded plastic sheet and are placed within the panel of the backpack that contacts the user""s back. The frames of these internal frame backpacks are typically more flexible than conventional external frames and more evenly distribute the load of the backpack across the user""s back. However, the flexible frames of internal backpacks are typically even less effective than rigid external backs at properly distributing the load to the hips and outer lumbar region of the user.
Also, in prior art backpacks having internal frames, the frame sheet tends to become distorted from its original shape under the weight of the backpack""s load. Specifically, the frame sheet tends to become cylindrical in shape as the sides of the frame are pulled toward one another by the forces created by the weight of the backpack""s contents. When this occurs, the distorted frame sheet causes weight to be unevenly distributed across the user""s back and the backpack becomes increasingly uncomfortable. Further, the backpack is unstable and tends to pivot on the user""s back since the load is applied centrally instead of at balanced points on either side of the user""s body. Since internal frame backpacks typically do not properly distribute the backpack""s load and the frame sheet has a tendency to become distorted, xe2x80x9csoftxe2x80x9d internal frame backpacks are generally ineffective for transporting large loads. Another disadvantage of internal frame backpacks is that the shape of the pack bag is dictated largely by the shape of the frame. Accordingly, internal frame backpacks do not effectively store contents that could otherwise be retained in the backpack.
In order to overcome these and other disadvantages, a backpack with a flexible pack frame that will concentrate the load of the backpack at the user""s hips and shoulders while comfortably fitting the user""s back is needed. Also, a flexible xe2x80x9csoftxe2x80x9d frame backpack that can support heavy loads while retaining its original shape is needed. Further, a comfortable backpack is needed that can retain a greater variety and amount of items. Moreover, a backpack is needed that will stabilize the load created by the backpack""s contents on the user""s body.
It is an object of the present invention to provide a backpack that properly distributes the load of the pack bag to the back, shoulders and hips of the user.
A further object of the present invention is to provide a backpack having a modular pack frame that does not become distorted by the forces created by the loaded backpack.
Still another object of the invention is provide a backpack that applies a stabilized load to the user""s body.
Another object of the invention is to provide a backpack with a flexible frame having additional storage spaces.
Accordingly, the present invention provides for a backpack having a pack bag and a modular pack frame. The modular pack frame includes a generally flexible frame sheet that is fixed to a rigid support bar at the center of the frame that is contoured to mimic the shape of a user""s backbone. The frame sheet is similarly curved and adapts to fit the remainder of the user""s back. A pad overlies the sheet and extends throughout the pack frame. A plurality of other reinforcement members are positioned in the pack frame and pack bag that prevent distortion of the pack frame and help to comfortably distribute the load to the user""s shoulders, hips, and back.
The modular pack frame is attached to the pack bag at a number of points so as to prevent the frame from becoming distorted. First, the pack frame is secured to the top of the pack bag by a pair of straps originating along the top of the shoulder pads. Second, a rod, positioned in generally axial alignment with the support bar, is coupled at either end by opposing bearings on the pack frame and telescoped within a sleeve located adjacent the rigid support bar of the pack frame. Further, the modular pack frame is connected to the pack bag by a pair of straps at the upper left and right portions of the pack frame and pack bag at a position proximate the flat portion of the user""s shoulders. The straps are releasably fastened to the opposing straps on the pack bag at mating male and female buckle members. Additionally, the modular pack frame is secured to hip belts flaps on the pack bag by patches of VELCRO(copyright) fasteners at the lower right and left side flaps of the pack frame. The pack bag and pack frame are also attached at a centrally located bottom flap. The weight of the backpack""s contents and the tension created by a hip belt of the backpack cause a concentrated, compression load at the area where the hip belt connects to the pack frame. Accordingly, this load is transmitted to the pad of the pack frame and the load is safely and comfortably transferred to the user""s body. Moreover, since the pack frame and hip belt envelopes the user""s body without substantially altering the generally flat rear panel of the pack bag, open storage spaces are formed between the outer edges of the pack bag and pack frame.
Additional objects, advantages and novel features of the invention will be set forth, in part, in a description which follows, and in part, will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention.